Electromechanical circuit breakers typically require several line cycles to open a fault current, so conventional fault coordination solutions used for electromechanical circuit breakers have a great amount of time to function. Such solutions may not be feasible in systems using static circuit breakers, which are typically much faster and may interrupt fault currents in less than a millisecond.
Although static circuit breakers may be faster, they typically cannot open for fault current having an amplitude several times the breaker nominal operating current. Accordingly, it is desirable that a static circuit breaker operate quickly. A typical static circuit breaker includes power semiconductor switches, such as insulated-gate bipolar transistors (IGBTs) or integrated gate-commutated thyristors (IGCTs) that are configured for uni- or bi-directional conduction. To deal with thermal limitations of these devices, a solid circuit breaker may interrupt the current before it reaches 200 percent of the nominal operating current.